Sodium hydride → HCID 118114408, compound

To a solution of (R)-tert-butyl 3-aminopiperidine-1-carboxylate (50 g, 250 mmol) and Et3N (50.5 g, 500 mmol) in DCM (500 mL) was added 2-chloroethyl isocyanate (31.65 g, 300 mmol) dropwise. The resulting mixture was stirred at RT for 4 hours before being quenched with water (100 mL). The layers were separated and the organic layer was washed with brine, dried, concentrated, and subjected to silica flash column using 0 to 50% EA in to isolate (R)-tert-butyl 3-(3-(2-chloroethyl)ureido)piperidine-1-carboxylate (364) (63.6 g, 81.5%) as a colorless oil. At 0° C., to a solution of (R)-tert-butyl 3-(3-(2-chloroethyl)ureido)piperidine-1-carboxylate (364, 31.0 g, 102 mmol) in anhydrous THF (350 mL) was added NaH (60% in mineral oil, 4.82 g, 122 mmol) in small portions slowly. The resulting mixture was stirred at RT for 6 hours before being quenched with water (50 mL). The layers were separated and the aqueous was extracted with DCM (20 mL×3). The combined organic layers were washed with brine, dried, concentrated and subjected to silica flash column using 0 to 5% MeOH in DCM to isolate (R)-tert-butyl 3-(2-oxoimidazolidin-1-yl)piperidine-1-carboxylate (365) (25.4 g, 93%) as a white solid. At 0° C., to a solution of (R)-tert-butyl 3-(2-oxoimidazolidin-1-yl)piperidine-1-carboxylate (365) (16.2 g, 60.2 mmol) in anhydrous THF (160 mL) was added NaH (60%, 3.6 g, 90.3 mmol) in small portions. The resulting mixture was stirred at RT for 30 min, cooled back to 0° C., and then iodomethane (12.9 g, 90.3 mmol) was added dropwise. After the addition, the mixture was stirred at RT for 3 hours. The reaction was quenched with water and extracted with DCM (50 mL×2). The combined organic layers were washed with brined, dried, concentrated, and purified by silica flash column using 0 to 3% MeOH in DCM to get (R)-tert-butyl 3-(3-methyl-2-oxoimidazolidin-1-yl)piperidine-1-carboxylate (366) (13.0 g, 74%) as a light yellow oil. (R)-tert-butyl 3-(3-methyl-2-oxoimidazolidin-1-yl)piperidine-1-carboxylate (366) (3.5 g, 12.37 mmol) was treated with 40 mL commercial 4N HCl in dioxane at RT for 2 hours. The solvent was removed in vacuo, and the residue was basified to pH 9 with ammonium hydroxide. The solvent was then removed in vacuo, and the residue was subjected to silica flash column using 0 to 10% MeOH in DCM to isolate (R)-1-methyl-3-(piperidin-3-yl)imidazolidin-2-one (367) (1.2 g, 53%) as an oil. LC-MS (ESI): m/z (M+1) 184.2. Proton NMR (CDCl3): δ 3.95-3.83 (2H, m), 3.75 (1H, s), 3.39-3.26 (5H, m), 3.08-2.97 (1H, m), 2.93-2.79 (1H, m), 2.78 (3H, s), 1.94-1.86 (2H, m), 1.82-1.56 (2H, m), 1.48-1.21 (1H, m) ppm.

1. custombefore being quenched with water (50 mL)
2. customThe layers were separated
3. extractionthe aqueous was extracted with DCM (20 mL×3)
4. washThe combined organic layers were washed with brine
5. customdried
6. concentrationconcentrated

ORD record

ord-56b6605e0d4a45c191ab207eaa37bf3f

Source dataset

uspto-grants-2016_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09382246B2